Ice on suction line

[Acrisoft]

Hi

I heard that when there is ice on suction line, it's because there is too much or little refrigerant in the system.

But as when there is little refrigerant, the system is superheated, I don't understand why there will be ice on suction line.

I would appreciate if someone could clarify it.

Moises

[chillerman2006]

suction lines below freezing point will ice and should be insulated

also could be a sign of liquid flood back caused by low superheat

R's chillerman

[Acrisoft]

Chillerman

I agree with you and understand that "...could be a sign of liquid flood back caused by low superheat".

Too much refrigerant = low superheat

But why people say that not enough refrigerant can also cause the suction line to freeze,
as less refrigerant = high superheat

Or this last statement is not true ?

Moises

[chillerman2006]

maybe your thinking of tev to evap distributor

which frosts when low charge or restriction in valve

R's chilleramn

[Acrisoft]

maybe your thinking of tev to evap distributor

which frosts when low charge or restriction in valve

R's chilleramn

Please let me remake my question.

I am not talking about TEV systems.

When it comes to min-split, only too much refrigerant can cause the suction line to ice,
or less refrigerant too ?

[Acrisoft]

When there is ice on the suction line of a refrigerator close to the compressor, can it only be refrigerant excess or lack or refrigerant too ? And why lack of refrigerant would cause the suction line to frost ?

[install monkey]

poor evap coil performance ,dirty filters can cause the same symptoms, also pipework can frost too where there is no lagging

[Tesla]

Hi Moises
Simply when a split system is short of gas the pressure of the suction line is reduced so the temperature of the refrigerant is reduced and the pipe which causes ice to form on the suction line.

[mikeref]

Eh Tesla? You might want to re-read your comment.:eek: If you're down on liquid volume then there won't be enough fluid to make it through the evaporator.. Sensible heat gain will start long before vapour makes it to the suction line.:)

[Goober]

I agree with Tesla, I call it for want of a better term a "sweet point" when a system is "just" short of refrigerant to do as Tesla says...lower the back pressure to allow freezing. Obviously the "sweet point" won't last long as the system continues to loose refrigerant.

[Mick13]

due to a lack of refrigerant in the evaporator it will boil off quicker and superheat will increase, resulting in a warmer suction line.
however, frost leaving the metering device will creep through the coil as ice acts as an insulator, eventually icing up the whole coil, then as the coil isnt absorbing heat due to the insulating nature of the ice, the refrigerant wont boil off and u may then get frost forming on your suction line.

[R. skiffington]

On a domestic system, ice on the suction line would definitely not indicate a shortage of refrigerant, either too much or possibly heavily iced up

[Tesla]

OK I did say simply but let me add a few more terms like slightly short of gas. If we took say a with a simple thermostat/capillary control etc and/or other. It does happen - I have seen it on units slightly short. The comp still pumps the same volume of lesser quality, with less gas the unit runs almost continuously with unsatisfactory cooling in space with iced/frosteing coil and suction line resulting.
Thanks Goober

[Acrisoft]

OK I did say simply but let me add a few more terms like slightly short of gas. If we took say a with a simple thermostat/capillary control etc and/or other. It does happen - I have seen it on units slightly short. The comp still pumps the same volume of lesser quality, with less gas the unit runs almost continuously with unsatisfactory cooling in space with iced/frosteing coil and suction line resulting.
Thanks Goober

Thank you Tesla
Now I understand why people say less refrigerant may cause ice.

About 20 years ago, when digital scales were very expansive, I was learning to repair refrigerators,
charging by gauge, I saw ice on suction line then I supposed it has too much refrigerant and then I removed refrigerant, and still saw ice, and the system was never OK.
I think many beginners without a scale will have a hard time, and do not understand why this happen.

Moises